Digital Printing: Meeting the Need for Personalized Printing of Fabrics

The 21st century is the era of science and technology and the era of digital. With the maturity of technology and markets, textile digital printing has achieved rapid development in recent years, and it has been able to meet the growing personal needs of people.

Digital direct injection according to the type of fabric and dye type can be divided into acidic direct-injection printing (silk, nylon), active direct-injection digital printing (cotton, linen, silk), dye-sublimation direct-injection printing (polyester), paint direct-injection printing (Almost all materials of pieces, clothing). According to the form of the fabric, it can be divided into two types: continuous direct-injection printing and direct-discharge printing. According to the characteristics of different fabrics with different elasticity and different brittleness, direct-discharge printing with direct-flow printing and direct-injection printing with non-conductive belts have emerged. Different types of printing equipment are suitable for different fabrics. At present, there is no real "universal" machine that can achieve all the components of all forms of fabric printing, but the degree of application of different devices is still a certain difference.

The main characteristics of direct-injection printing equipment include printing precision, equipment stability, ease of operation, ease of maintenance, and adaptability. This article only analyzes the printing accuracy for your reference.

When referring to the printing accuracy, everyone will always ask how much the resolution of the printing is 1440dpi or 720dpi. In fact, this is only part of the printing accuracy, which will involve the resolution of the print head, mechanical precision (step accuracy, mechanical precision of the shaft roller). There are three main aspects of the matching degree of ink, ink and showerhead.

First talk about nozzle accuracy. At present, the nozzles on the market include piezoelectric nozzles, thermal foaming nozzles, photo-use nozzles, and industrial nozzles. Among them, the most commonly used print heads are piezoelectric photo heads and industrial heads. Piezoelectric photo inkjet heads are based on EPSON's four-generation heads, five-generation heads and six-generation heads. Five generations of the head is the mainstream product, the highest resolution is 1440dpi, support 720dpi, 540dpi print mode, this is also the most used print head. In addition, some manufacturers, such as the United States SPETRA, Japan's Ricoh, Japan KYOCERA selected industrial nozzles, industrial head resolution is generally about 720dpi. Industrial head and EPSON nozzle compared to the high price, but long life, low resolution, large drops of ink; but from the textile printing point of view, because the fabric of the fiber is relatively thick, 720dpi resolution, from the visual effect is It is difficult to distinguish. From the nozzle point of view, because the nozzle technology is monopolized by a few manufacturers, printing machine manufacturers are purchased from these manufacturers, so, in fact, if you choose the machine printing accuracy, the nozzle is basically the starting point is the same.

Secondly, the impact of mechanical precision on printing is actually much greater than the resolution of the nozzle, because the machining is still not high at the domestic level. The width of the general printing machine is 1600mm~2200mm, and the length of the shaft roller is generally 2200mm~2800mm. Taking the Italian MS guided belt direct printing as an example, the shaft diameter is 400mm and the length is 2200mm. The overall error of the shaft diameter, concentricity and straightness is 0.003mm, ie, the mechanical error of printing one circumference is 0.01mm. The difficulty of such an axis can be imagined. But similarly, we can also imagine that if the diameter of a company's product is 0.1mm in diameter, then in the printing process, the nozzle may cross at one side of the two ink jets, and the other side may have 0.3mm. The appearance of the white line is unacceptable to any customers. Similarly, if there is a problem with the degree of concentricity and straightness, the situation is similar.

Accuracy of assembly is not enough. It is also the main reason that affects the accuracy of printing machinery. For example, parallelism is not enough, resulting in fabric deviation, bearing quality but off, inconsistent wear, will also affect the problem of parallelism.

Servo motor and control system, in addition to a few small factory products, will generally use international brands of products, little effect on the mechanical accuracy.

The third is ink. Most people think that ink may affect color saturation, color fastness, and coloring. In fact, ink also has a great influence on printing accuracy. What is more obvious is that if the ink has poor fluency and there are many mechanical impurities, thread breakage and plugging may occur, and small white lines appear in the printing process, which affects the printing accuracy. If the viscosity of the ink, surface tension and other parameters have problems, it may cause oblique spray. Then there is the preservation stability of the ink, the unity between the batch product and the next batch of products, etc., are the main reasons causing quality problems.

In summary, we want to get a good print quality, get a good printing accuracy, can not only focus on the resolution of the nozzle, mechanical precision, the quality of the optional ink is also very important.